= Upgrading from v3 to v4

The configuration for v4 is _somewhat_ compatible with the v3
configuration. It should be possible to reuse most of a v3
reconfiguration with minor tweaks.

NOTE: This file describes the differences between v3 and v4. It does not
contain a step-by-step process for upgrading the server.

In general, we have the following changes:

* most module configuration is very close to v3.
* most of the `unlang` processing is very close to v3.
  * `update` is now replaced just by editing the attribute in place.
* each `server` section need a `namespace` parameter.
* Packet processing sections are now `recv Access-Request`, etc. Not
  `authorize`, etc.
* each `listen` section needs to be converted to the v4 format.

== Upgrading from older versions

=== Upgrading from v3

When upgrading, please start with the default configuration of v4. Then,
move your v3 configuration over, one module at a time. Check this file
for differences in module configuration, and update the module to use
the new configuration. Start the server after every change via
`radiusd -XC` to see if the configuration is OK. Then, convert the
`listen` sections, followed by the `server` sections.

Take your time. It is better to make small incremental progress, than
to make massive changes, and then to spend weeks debugging it.  Use a
revision control system such as `git` to save and track your changes.
If the changes work as you expect, do `git commit`, and continue with
the next change.  If the changes do not work, either keep at it, or
move to a different portion of the configuration

All of the attribute names used in v3 have been changed in v4.  Please
see the xref:attribute_names.adoc[attribute names] document for more
information.  This change was necessary in order to support the new
"grouped" attributes, which are required for DHCPv6 and other
protocols.

=== Upgrading from v2

If you are upgrading from v2 you should read the v3 version of this
file.  It describes changed from v2 to v3. This file describes only
the changes from v3 to v4.

== Attribute Names

Much of the information in this section is also in the
`raddb/dictionary` file

All of the attributes have been renamed from v3.  This change was
necessary in order to support new functionality in v4.  The
unfortunate side effect of this change is that all of the names in
SQL, LDAP, and the `files` module are incompatible with v4.

We recognize that is is difficult to change every entry in a
database, especially when there's no clear mapping between the
"old" and "new" names.  This renaming is made more complex because
the "new" names need to be grouped and arranged in ways that the
old ones were not.

The "old" names were all in flat lists, so that `User-Name` appeared
next to `Cisco-AVPAir`.  This organization was simple enough to work
for 20 years, but its time has come.  The new names are hierarchical,
and are nested by definition.

For v4, the `Cisco-AVPair` attribute is called `AVPair`, and it lives
inside of the `Cisco` namespace, which in turn lives inside of the
`Vendor-Specific` namespace.  So the old `Cisco-AVPair` attribute is
now named `Vendor-Specific.Cisco.AVPair`.

This renaming process continues for many thousands of vendor-specific
attributes.

Happily, it is possible to (mostly) use the old names with v4.
There are limitations, but it will mostly work.  The main reason
for enabling the old names is to try out v4 with a database which is
also used by v3.  This lets you test that v4 works, without going
through a complex "upgrade everything" process.

The old v3 names are in "alias" dictionaries, in the
`${dictdir}/alias/` directory.  To find out where this directory is on
your local system, run "radiusd -h" or "radclient -h".  Then look for
the "-D" command-line option, and it will tell you where the
dictionary files are located.

The v3 names are in a file named `${dictdir}/radius/alias/VENDOR.txt` where
`VENDOR` is the name of the vendor, which is taken from the `VENDOR`
definition in the v3 dictionaries.

You will need to add a `$INCLUDE` line for each vendor-specific
dictionary which is used by your local system.  The default v4
dictionaries do not enable all of v3 compatibility names.  The reason
is simple: the alias names _mostly_ work, in most situations.  But
there are situations where the aliases do not behave correctly.

We recognize that this process is a bit of work.  However, we wish to
encourage everyone using v4 to upgrade to using the new v4 features.
Our experience shows that if we automatically enable "compatibility
features", then those compatibility features will be used for a decade,
and no one will upgrade to use the new features.  So we need to find a
balance between upgrades and ongoing support.  Easy upgrades will mean
complex ongoing support.  Complex upgrades make ongoing support
easier, but also make it less likely that people will upgrade.

== radiusd.conf

The following configurations have been removed. See the new `listen`
sections for their replacements.

[width="100%",cols="30%,70%",options="header",]
|===
| v3              | v4
| `cleanup_delay` | replaced with `cleanup_delay` in a `listen` section.
| `reject_delay`  | see `mods-available/delay`. You should list `delay`
                    last in any `send Access-Reject` section.
| `status_server` | see `type = Status-Server` in a new `listen` section.
|===

The `log` section has been updated to remove many configuration items
which are specific to RADIUS, and to Access-Request packets. Please see
`sites-available/default`, and look for the `Access-Request`
subsection there. See also xref:raddb:templates.conf.adoc[`templates.conf`]
for a way to regain one global configuration for `Access-Request`
packets.

=== Instantiate Section

The `instantiate` section has been removed.  It originally started out
as a way to ensure that modules were instantiated in a particular
order.  A later use of the `instantiate` section was to define
"virtual modules" for dynamic expansion.  That functionality has been
moved to the `mods-available/` and `mods-enabled/` directories.
i.e. in version 4, just list the virtual module in a file, as if it
was a real module.

See the xref:raddb:mods-available/redundant_sql.adoc[redundant_sql] module
for more information.  In short, a virtual module can be put into
the `mods-enabled` directory as with any other module, as with the
following text:

[source,unlang]
----
redundant redundant_sql {
	sql1
	sql2
}
----

In this case, this definition creates a `redundant_sql` virtual module.


== Virtual Servers

There are some changes to the virtual servers in `v4`. First, every
virtual server has to begin with an entry:

```
namespace = ...
```

For RADIUS, use:

```
namespace = radius
```

This tells the server what protocol is being used in that virtual
server. This configuration was not necessary in v3, because each
protocol was pretending to be RADIUS. That was simple to program at
the time and worked for some things, but it was not the best approach.

In v4, each protocol is completely independent, and RADIUS is no
longer built into the server core.  i.e. The server core does modules,
configuration files, policies, etc.  RADIUS has been relegated to just
another plug-in protocol, with the same status as DHCPv4 and DHCPv6.

Every example virtual server in the `sites-enabled/` directory
contains a `namespace` parameter.  Please look at those files for
examples of configuring and running each supported protocol.

=== Listen Sections

The `listen` sections have changed. There is now a `type` entry, which
lists the packet type by their correct name (e.g._`Access-Request`
instead of `auth`). To accept multiple kinds of packets, just list
`type` multiple times:

```
type = Access-Request
type = Accounting-Request
```

Each `listen` section also has a `transport` entry. This
configuration can be left out for `headless` servers, such as
`inner-tunnel`. For example, setting UDP transport is done via:

```
transport = udp
```

Each type of transport has its configuration stored in a subsection
named for that transport:

```
transport = udp
udp {
    ... udp transport configuration ...
}
```

For `udp`, the configuration entries are largely the same as for v3.
e.g. `ipaddr`, `port`, etc.

The `listen` section then compiles each
xref:index.adoc#_processing_sections[Processing Section] based on the named packet
types. It has a `recv` section for receiving packets, and a `send`
section for sending packets, as seen in the following example:

[source,unlang]
----
recv Access-Request {
   ... unlang ...
}

send Access-Accept {
    ... unlang ...
}
----

This configuration is different from v3. The benefit of the change is
that it is much easier to understand. Instead of using confusing names
such as `Post-Auth-Type Reject`, the server now just uses `send
Access-Reject`.

See also xref:index.adoc#_processing_sections[Processing Section] for how the
`unlang` statements are parsed.

=== Clients

The server supports global clients in the `clients.conf` file, as with
v3.

Client can also be defined in a `client` subsection of a virtual
server. Unlike `v3`, there is no need to have a `clients` section
which "wraps" one or more `client` definitions. See
`sites-available/default` for examples.

The server also supports dynamic clients. See
`sites-available/dynamic_clients` for a worked example. There are many
changes from v3. First, there is no need to have a `client` definition
which contains a network. Instead, there is a `network` section which
has a number of `allow` and `deny` rules. Second, dynamic clients
can be defined on a per-connection basis. Finally, the
`sites-available/dynamic_clients` virtual server has full access to
the entire RADIUS packet.

The result of these changes is that it is now possible to have multiple
clients behind a NAT gateway, and to have different shared secrets for
each client. e.g._by keying off of the `NAS-Identifier` attribute.

The dynamic client functionality behaves the same for all protocols
supported by the server. e.g. RADIUS, DHCP, VMPS, TACACS+, etc.

== Processing Sections

All of the processing sections have been renamed. Sorry, but this was
required for the new features in v4.

[cols=",",options="header",]
|===
| Old Name                   | New Name
| `authorize`                | `recv Access-Request`
| `authenticate`             | `authenticate <Auth-Type>`
| `post-auth`                | `send Access-Accept`
|                            |
| `preacct`                  | `recv Accounting-Request`
| `accounting`               | `accounting %\{Acct-Status-Type\}`
| `accounting`               | `send Accounting-Response`
|                            |
| `recv-coa`                 | `recv CoA-Request`
| `send-coa`                 | `send CoA-ACK`
| `send-coa`                 | `send CoA-NAK`
|                            |
| `Post-Auth-Type Reject`    | `send Access-Reject`
| `Post-Auth-Type Challenge` | `send Access-Challenge`
|===

i.e. instead of the section names being (mostly) randomly named, the
names are now consistent. The `recv` sections receive packets from the
network. The `send` sections send packets back to the network. The
second name of the section is the _type_ of the packet that is being
received or sent.

NOTE: For accounting, packets are also processed through an
`accounting` section named after Acct-Status-Type. This process is
similar to `authenticate` for `Access-Request` packets. The goal
here is to allow a common pre-processing of accounting packets in the
`recv Accounting-Request` packet, followed by type-specific processing
in `accounting %{Acct-Status-Type}`. See sites-available/default for
examples and more information.

=== update sections

A major difference between v3 and v4 is that `update` sections are no
longer necessary.  It is now possible to just edit attributes "in
place", as with:

See the xref:reference:unlang/update.adoc[update] documentation for a
description of what has changed, and how to use the attribute new
xref:reference:unlang/edit.adoc[edit] functionality.

For example, instead of doing this:

[source,unlang]
----
if (&User-Name == "bob") {
    update reply {
        &Reply-Message := "Hello, %{User-Name}"
    }
}
----

You can now do this:

[source,unlang]
----
if (&User-Name == "bob") {
    &reply.Reply-Message := "Hello, %{User-Name}"
}
----

As with any upgrade across major version numbers, there are caveats.
See the full xref:reference:unlang/update.adoc[update] documentation
and xref:reference:unlang/edit.adoc[edit] documentation for details.

== Proxying

Proxying has undergone massive changes. The `proxy.conf` file no
longer exists, and everything in it has been removed. e.g. `realm`,
`home_server`, `home_server_pool` no longer exist. The old proxying
functionality was welded into the server core, which made many useful
features impossible to configure.

The `radius` module now handles basic proxying to home servers. We
recommend creating one instance of the `radius` module per home
server. e.g.

[source,unlang]
----
radius home_server_1 {
   ... configuration for home server 1 ...
}
----

You can then use `home_server_1` in any processing section, and the
request will be proxied when processing reaches the module.

For ease of management, we recommend naming the modules for the host
name of the home server.

It is often simplest to do proxying via an `authenticate proxy { ... }`
section, though that section can have any name. e.g. setting
`Auth-Type := proxy` will call the `authenticate proxy` section, and
is similar to the previous setting `Proxy-To-Realm`.

[source,unlang]
----
authenticate proxy {
    home_server_1
}
----

For more detailed examples, see the Wiki page:
https://wiki.freeradius.org/upgrading/version4/proxy. That page also
describes how to upgrade a v3 configuration to the new v4 style.

The benefit of this approach is that the "RADIUS proxy" functionality
is just another module.  It is now possible to not just fail over from
one home server to another, but also to proxy the same packet to
multiple destinations.

=== home_server

The `home_server` configuration has been replaced with the `radius`
module. See `raddb/mods-available/radius` for examples and
documentation.

=== home_server_pool

The `home_server_pool` configuration has been replaced with standard
unlang configurations. The various load-balancing options can be
re-created using in-place `unlang` configuration.

The mappings for `type` are as follows:

* `type = fail-over` - replaced with `unlang`

[source,unlang]
----
redundant {
    home_server_1
    home_server_2
    home_server_3
}
----

NOTE: Of course, you will have to use the names of the `radius`
modules in your configuration, and not `home_server_1`, etc.

* `type = load-balance` - replaced with `unlang`

[source,unlang]
----
load-balance {
    home_server_1
    home_server_2
    home_server_3
}
----

* `type = client-balance` - replaced with `unlang`

[source,unlang]
----
load-balance "%{Net.Src.IP}" {
    home_server_1
    home_server_2
    home_server_3
}
----

* `type = client-port-balance` - replaced with `unlang`

[source,unlang]
----
load-balance "%%{Net.Src.IP}-%{Net.Src.Port}" {
    home_server_1
    home_server_2
    home_server_3
}
----

* `type = keyed-balance` - replaced with `unlang`

[source,unlang]
----
load-balance "%{Load-Balance-Key}" {
    home_server_1
    home_server_2
    home_server_3
}
----

While the `Load-Balance-Key` was a special attribute in v3, it has no
special meaning in v4. You can use any attribute or string expansion as
part of the `load-balance` key.

=== Things which were impossible in v3

In v3, it was impossible to proxy the same request to multiple
destinations. This is now trivial. In any processing section, do:

[source,unlang]
----
...
home_server_1
home_server_2
...
----

When processing reaches that point, it will proxy the request to
`home_server_1`, followed by `home_server_2`.

This functionality can be used to send `Accounting-Request` packets to
multiple destinations.

You can also catch _failed_ proxying, and do something else. In the
example below, try to proxy to `home_server_1`, if that fails, just
`accept` the request.

[source,unlang]
----
...
home_server_1
if (fail) {
    accept
}
...
----

=== CoA and Originate-Coa

The `sites-available/originate-coa` virtual server has been updated to
use the new `subrequest` feature.  Please see that virtual server, and
the `subrequest` keyword for details.

== Dictionaries

The `struct` data type is now supported. See `man dictionary`.

Bit fields are now support via a data type such as `bit[3]`.  Not that
bit fields are _only_ supported inside of a `struct` definition.

The dictionary parser includes many more sanity checks and helpful
messages for people who create new dictionaries.

Dictionaries are now split up by protocol.
e.g._`share/freeradius/radius/dictionary*`.  All protocol-specific
data types have been removed, and replaced with per-attribute flags.

The old `abinary` data type has been removed.  Attributes needing this
functionality should instead be marked with a flag, e.g._`string abinary`.

The old `extended` data type has been removed. Attributes needing this
functionality should instead be marked with a flag, e.g._`tlv
extended`.

=== "Tagged" RADIUS attributes

The old-style "tagged" RADIUS format has been removed.  Instead of using

[source,unlang]
----
Tunnel-Type:1 = PPTP
----

you should use

[source,unlang]
----
Tag-1.Tunnel-Type = PPTP
----

It is also possible to "group" tagged attributes together, as in the
following example:

[source,unlang]
----
Tag-1 = { Tunnel-Type = PPTP, Tunnel-Medium-Type = IPv4 }
----

There are 31 such attributes, `Tag-1` through `Tag-31`.  There is no
`Tag-0` attribute, as it is not needed.

After much investigation, it was unfortunately impossible to continue
supporting the `Attribute-Name:tag` syntax for tagged attributes.
This change requires modifications to all configuration files and
databases which use tags.  This change means also that `detail` files
from v3 are not readable by v4.

== Attribute references

In previous versions of the user attributes could be referred to by
their name only e.g. `if (User-Name == 'foo')`.

To allow for more thorough error checking, it is now required to
prefix attribute references with `&`.  Using bare names will result in
an error, and a suggestion to use `&`.

Common places which will need to be checked and corrected are the left
and right hand side of `update {}` sections, along with `if` conditions.

The v3 server has warned about using non prefixed attribute references
for some time. If users have addressed those warnings, few
modifications will be required.

Use of attributes in xlats e.g. `%{User-Name}` remains unchanged.
There is no plan to require prefixes here.

As of v3, the preferred format for `unknown` attributes is
`&Attr-oid.oid.oid`, e.g. `&Attr-26.11344.255`. However, v3 would
still parse (but not generate) attributes of the form
`Vendor-FreeRADIUS-Attr-255`. The `Vendor-` syntax has been removed in
version 4. The server would never produce such names, and allowing
them as input made attribute parsing significantly more complex.

=== List references

The old-style `request:` and `reply:` syntax for lists has been
deprecated.  Please use `request.` and `reply.` instead.

Many lists have been removed.  e.g._`proxy`, `proxy-reply`, `coa`,
`coa-reply`, `disconnect`, and `disconnect-reply`.  The underlying
functionality still exists, but it has been moved to different
keywords, such as `subrequest`.

== Update sections

The `update` sections are deprecated.  See the new way to
xref:reference:unlang/edit.adoc[edit attributes].

The server has limited support for "auto-conversion" of `update`
sections to the new syntax.

=== Recommendations

We recommend manually converting the `update` sections to the new
method.  The biggest change that confuses people is the old `+=`
operator does not work the same way as before.

Instead of doing:

```
&Reply-Message += "foo"
```

you should edit the `reply` list, using the `+=` operator:

```
&reply += {
    &Reply-Message = "foo"
}
```

We also recommend removing double-quotes from xlat expansions where
possible.  The temptation in v3 is to just add double quotes to
everything, and hope it all works out.  This is no longer necessary in
v4.

For example, in v3 you would do:

```
update reply {
	&Framed-IP-Address := "%{sql:SELECT ...}"
}
```

In v4, you can remove the `update`, and rewrite the SQL call to:

```
&reply.Framed-IP-Address := %sql("SELECT ...")
```

Using double quotes everywhere means that every bit of data gets
converted to printable strings, and then back to it's real data type
(`ipaddr` in the above example).  Removing the double quotes means
that there is less work going on, which means higher performance.

== load-balance and redundant-load-balance sections

Before v4, the `load-balance` sections implemented load balancing by
picking a child at random. This meant that load balancing was
probabilistically fair, but not perfectly fair.

In v4, `load-balance` sections track how many requests are in each
sub-section, and pick the subsection which is used the least. This is
like the v3 proxy behavior of load balancing across home server pools.

The `load-balance` and `redundant-load-balance` sections now allow
for a load-balance key:

[source,unlang]
----
load-balance "%{Calling-Station-Id}" {
    module1
    module2
    module3
    ...
}
----

If the key exists, it is hashed, and used to pick one of the
subsections. This behavior allows for deterministic load-balancing of
modules, similar to the v3 proxy `keyed-balance` configuration.

== Connection timeouts

In v3 and earlier, the configuration items for configuring connection timeouts
were either confusingly named, or completely absent in the case of many
contributed modules.

In v4, connection timeouts can be configured universally for all modules
with the `connect_timeout` config item of the module’s `pool {}`
section.

The following modules will apply `connect_timeout`:

* rlm_rest
* rlm_linelog (network connections only)
* rlm_ldap
* rlm_couchbase
* rlm_cache_memcached
* rlm_redis_* (all the redis modules)
* rlm_sql_cassandra
* rlm_sql_db2
* rlm_sql_freetds
* rlm_sql_mysql
* rlm_sql_unixodbc

Some modules such as rlm_sql_postgresql can have their timeout set via
an alternative configuration item (e.g. `radius_db` in the case of
postgresql).

== Unlang Syntax

Many new xref:reference:unlang/index.adoc[unlang] keywords have been added.

Data type casts have changed from `<ipaddr> ...` to `(ipaddr) ...`

== Xlat expansions

xref:reference:xlat/index.adoc[xlat] expansions have been changed from syntax like `%{md5:...}` to `%md5(...)`.

=== Removed expansions

`%{integer:...}` has been removed.  Just use a cast, such as `(integer) &Service-Type`.

`%{expr:...}` has been removed.  You can instead use in-place expressions, such as `%{1 + 2}` or `%{&NAS-Port + 14}`.

== New Modules

The following modules are new in v4.

=== rlm_client

This module handles the `%{client:..}` xlat expansions.

The `Client-Shortname` attribute has been removed.  You should use `%client(shortname)` instead.

=== rlm_radius

The `radius` module has taken over much of the functionality of
`proxy.conf`. See `raddb/mods-available/radius` for documentation
and configuration examples.

The `radius` module connects to one home server, just like the
`home_server` configuration in v3. Some of the configuration items are
similar to the `home_server` configuration, but not all.

The module can send multiple packet types to one home server.
e.g. Access-Request and Accounting-Request.

This module also replaces the old `coa` and `originate-coa`
configuration. See also `subrequest` for creating child requests that are
different from the parent requests.

Unlike v3, the module can do asynchronous proxying. That is, proxying
where the server controls the retransmission behavior. In v3, the server
retransmitted proxied packets only when it received a retransmission
from the NAS. That behavior is good, but there are times where
retransmitting packets at the proxy is better.

== Changed Modules

The following modules exhibit changed behaviour.

=== rlm_cache

`&control.Cache-Merge` has been renamed to
`&control.Cache-Merge-New` and controls whether new entries are merged
into the current request. It defaults to `no`. The primary use case,
is if you’re using xlat expansions in the cache module itself to
retrieve information for caching, and need the result of those
expansions to be available immediately.

Two new control attributes `&control.Cache-Allow-Merge` and
`&control.Cache-Allow-Insert` have been added. These control whether
existing entries are to be merged, and new entries created on the next
call to a cache module instance. Both default to `yes`.

=== rlm_eap

All certificate attributes are available in the `&session-state.`
list, immediately after they are parsed from their ASN1 form.

The certificates are no longer added to the `&request.` list. Instead,
they are added to the `session-state` list.  You are advised to update
any references during the upgrade to 4.0:

```
s/TLS-Cert-/session-state.TLS-Cert-/
```

The `rlm_eap_ikev2` module was removed. It does not follow RFC 5106,
and no one was maintaining it.

The `rlm_eap_tnc` module was removed. No one was using or maintaining
it.

The in-memory SSL cache was removed. Changes in OpenSSL and FreeRADIUS
made it difficult to continue using the OpenSSL implementation of a
cache. See `raddb/sites-available/tls-cache` for a better replacement.
The OpenSSL cache can now be placed on disk, in memory, in memcache,
or in a redis cache. The result is both higher performance, and more
configurable.

The `use_tunneled_reply` and `copy_request_to_tunnel` configuration
items have been removed. Their functionality has been replaced with the
`use_tunneled_reply` and `copy_request_to_tunnel` policies. See
`raddb/sites-available/inner-tunnel` and `raddb/policy.d/eap` for
more information.

These configuration items were removed because they caused issues for a
number of users, and they made the code substantially more complicated.
Experience shows that having configurable policies in `unlang` is
preferable to having them hard-coded in C.

=== rlm_eap_pwd

The `virtual_server` configuration has been removed from EAP-PWD. The
module now looks for &request.control.Password.Cleartext.

=== rlm_eap_leap

The LEAP protocol has been removed from the server.  It is insecure,
non-standard, and should not be used.

=== rlm_exec

Exec-Program and Exec-Program-Wait have been removed.

The `packet_type` configuration has been removed. Use `unlang`
checks to see if you want to execute the module.

=== rlm_expr

The `expr` module is no longer necessary and has been removed.

The xref:reference:xlat/index.adoc[xlat] expansions just support math
natively.  For example:

```
&Reply-Message := "1 + 2 = %{1 + 2}"
```

will return the string `1 + 2 = 3`.  The contents of the expansion can
be any math or condition.  Attribute assignments in expansions are not
supported.

=== rlm_expiration

The `expiration` module has been replaced with an `unlang` policy.
The policy is located in `raddb/policy.d/time`.  The `Expiration`
attribute should continue to work the same as with v3.

=== rlm_ldap

The `ldap` module provides an expansion `%ldap.group(<name>)` instead of
`LDAP-Group` for dynamically testing group membership.  The old method of

```
if (LDAP-Group == "foo") { ...
```

will no longer work.  Instead, use

```
if (%ldap.group(foo)) { ...
```

The caching of group membership into attributes in the `control` list is
still available, so

```
&control.LDAP-Group[*] == "foo"
```
can also be used to test membership after having called the `ldap` module,
if `cacheable_name` or `cacheable_dn` are enabled.

=== rlm_mschap

The `winbind_*` configuration options are now in a `winbind`
subsection. See `mods-available/mschap` for details.

=== rlm_perl

Attributes of type `octets` are now passed directly to Perl as binary
data, instead of as hex strings.

All data received from the network is marked `tainted` by default.

=== rlm_radutmp

The `case_sensitive` option has been removed.  Administrators should
not be permitting users to log in with multiple different user names.
If your system needs to be case insensitive, we suggest changing all
names to lowercase:

```
recv Access-Request {
	&Stripped-User-Name := %tolower(%{User-Name})
	...
}
```

=== rlm_rest

`REST-HTTP-Code` is now inserted into the `&request.` list instead
of the `&reply.` list, to be compliant with the
https://wiki.freeradius.org/guide/List-Usage[list usage] guidelines.

=== rlm_sql

Driver-specific options have moved from `mods-available/sql` to
`mods-config/sql/driver/<drivername>`.

If caching is enabled, the `SQL-Group` attribute is cached in the
`control` list after the module has run.  This means it is possible to
do regular expression comparison on group names.

It also means that any comparison of `&SQL-Group == "foo"` has to be
updated to use `&control.SQL-Group == "foo"` instead.

This caching also means that the group comparison will be done
internally, and will not result in a database lookup.  This also means
that it is now possible to do group comparisons based on regular
expressions.

It is possible to force a dynamic group lookup via the expansion
`%sql.group(foo)`.  This expansion returns `true` if the user is a
member of that SQL group, and `false` otherwise.

```
if (%sql.group(sales)) {
   ...
}
```

will return `true`.

==== Accounting and Post-Auth module calls

The `reference` option has been removed from `accounting` and `post-auth`
sql module configuration.

Instead, the set of queries run depend on the section the module is called
from.  E.g. calling from `accounting Start` will run the set of queries
defined as

```
accounting {
	start {
		query = ...
		query = ...
	}
}
```

The v3 `post-auth` configuration is now replaced with a set of `send`
queries, again with the queries run specific to the section that the
module is called from.

```
send {
	access-accept {
		query = ...
	}
	access-reject {
		query = ...
	}
}
```

==== Profiles

The `default_user_profile` has been removed.  No one used it, as that
behavior was already supported by the group functionality.  See
rlm_sql and `User-Profile` for new, and superior, behavior.

==== rlm_sql_mysql

Now calls `mysql_real_escape_string` and no longer produces
`=<hexit><hexit>` escape sequences in expanded values. The
`safe_characters` config item is ignored when using MySQL databases.

==== rlm_sql_postgresql

Now calls `PQescapeStringConn` and no longer produces
`=<hexit><hexit>` escape sequences in expanded values. The
`safe_characters` config item is ignored when using PostgreSQL
databases.

=== rlm_sqlcounter

Attribute references:

The following config items must now be defined as attribute references::

```
counter_name
check_name
reply_name
```

For example where in v3 you would specify the attribute names as::

```
counter_name    = Daily-Session-Time
check_name      = Max-Daily-Session
reply_name      = Session-Timeout
key             = User-Name
```

In v4 they must now be specified as::

```
counter_name    = &control.Daily-Session-Time
check_name      = &control.Max-Daily-Session
reply_name      = &reply.Session-Timeout
key             = "%{&Stripped-User-Name || &User-Name}"
```

Just adding the `&` prefix to the attribute name is not sufficient.
Attributes must be qualified with the list to search in, or add to.

This allows significantly greater flexibility, and better integration
with newer features in the server such as CoA, where reply_name can now
be `&coa:Session-Timeout`. That allows the server to send a CoA packet
which updates the `Session-Timeout` for the user.

In v4, when the `key` field was set to `User-Name`, the module would
also look for `Stripped-User-Name` as the key.  In v4, this
functionality has been moved to the configuration.  To get the same
functionality, the key should now be specified as a dynamic expansion:

```
key = "%{&Stripped-User-Name || &User-Name}"
```

The `count_attribute` has been removed, as it is no longer necessary.

The old expansions `%%b` and `%%e` have been removed.  This should
only affect people who are editing the queries manually.  See the file
`mods-availble/sqlcounter` for more information.

The attribute comparison has been removed.  It is no longer possible
to check `Daily-Session-Time > 4` everywhere.  Instead, the attribute
exists only after the `sqlcounter` module has been run.

=== rlm_sqlippool

NOTE: The `ipv6` configuration item has been deleted. It was
deprecated in 3.0.16.

Instead, use `attribute-name`. See `mods-available/sqlippool` for
more information.

=== rlm_unix

The `unix` module uses an expansion `%unix.group(<name>)` instead of
`Unix-Group`, `Group` or `Group-Name`.  The old method of doing

```
Group == "foo"
```

will no longer work.

=== rlm_winbind

The `winbind` module uses an expansion `%winbind.group(<name>)` instead of
`Winbind-Group == <name>`.

== Deleted Modules

The following modules have been deleted

=== rlm_counter

Instead of using this, please use the `sqlcounter` module with sqlite.

It is difficult to maintain multiple implementations of the same
functionality. As a result, we have simplified the server by removing
duplicate functionality.

=== rlm_ippool

Instead of using this, please use the `sql_ippool` module with sqlite.

It is difficult to maintain multiple implementations of the same
functionality. As a result, we have simplified the server by removing
duplicate functionality.

=== rlm_logintime

This module was poorly documented, and it appears that no one was using it.

The attributes `Time-Of-Day`, `Login-Time`, and `Current-Time` have
also been removed.  Any configuration which tries to use them will
result in an error.

Dates and time attributes can be checked against date strings by
casting them:

```
if (&Date-attribute < (date) 'Aug 1 2023 01:02:03 UTC') {
	...
}
```

The current time can also be checked:

```
if (%time() < (date) 'Aug 1 2023 01:02:03 UTC') {
	...
}
```

== Deleted Functionality

Many "virtual" or "fake" attributes have been removed or renamed.

`&Module-Return-Code` should be replaced by `%interpreter(rcode)`.

`&Response-Packet-Type` should be replaced by `&reply.Packet-Type`.

`&Virtual-Server` should be replaced by `%interpreter(server)`.

`&Packet-Authentication-Vector` should be replaced by `%radius.packet.vector()`.

`&Packet-Dst-IP-Address` and `&Packet-Dst-IPv6-Address` should be replaced by `&Net.Dst.IP`.

`&Packet-Dst-Port` should be replaced by `&Net.Dst.Port`.

`&Packet-Src-IP-Address` and `&Packet-Src-IPv6-Address` should be replaced by `&Net.Src.IP`.

`&Packet-Src-Port` should be replaced by `&Net.Src.Port`.

== Recommended Changes

In v3, many people had a habit of just adding `"..."` around _everything_.  For example:

.Bad practice - using "" everywhere
[source,unlang]
----
update reply {
	&Reply-Message := "%{User-Name}"
}

...

if ("%{User-Name}" == "bob") {
   ...
}
----

This practice is not recommended.  It was never necessary, and it's not clear why it became a (bad) habit.

In v4, it is clearer, simpler, and faster to just use `unlang` syntax correctly.

.Good practice - just rely on the server to do the right thing

[source,unlang]
----
&reply.Reply-Message := &User-Name

...

if (&User-Name == "bob") {
   ...
}
----
